Disable aggregation pushdown for Decimal type (#18595)

Author: zverevgeny

.github/config/muted_ya.txt

@@ -18,7 +18,6 @@ ydb/core/keyvalue/ut_trace TKeyValueTracingTest.WriteSmall
 ydb/core/kqp/ut/batch_operations [*/*] chunk chunk
 ydb/core/kqp/ut/cost KqpCost.OlapWriteRow
 ydb/core/kqp/ut/federated_query/s3 sole chunk chunk
-ydb/core/kqp/ut/olap KqpDecimalColumnShard.TestAggregation
 ydb/core/kqp/ut/olap KqpOlapDelete.DeleteWithDiffrentTypesPKColumns-isStream
 ydb/core/kqp/ut/olap KqpOlapDictionary.DifferentPages
 ydb/core/kqp/ut/olap KqpOlapJson.CompactionVariants

ydb/core/kqp/opt/physical/kqp_opt_phy_olap_agg.cpp

@@ -67,6 +67,11 @@ bool CanBePushedDown(const TExprBase& trait, TExprContext& ctx)
     }
     auto aggApply = trait.Cast<TCoAggApply>();
     auto aggName = aggApply.Name();
+    const auto& aggType = aggApply.Extractor().Ptr()->GetTypeAnn();
+    if (const auto& nakedType = RemoveOptionality(*aggType); nakedType.GetKind() == ETypeAnnotationKind::Data) {
+        if (GetDataTypeInfo(nakedType.Cast<TDataExprType>()->GetSlot()).Features & NUdf::EDataTypeFeatures::DecimalType)
+            return false;
+    }
     if (SupportedAggFuncs.find(aggName.StringValue()) != SupportedAggFuncs.end()) {
         return true;
     }